1. Field of the Invention
The present invention pertains to the air-carbon arc cutting and gouging process used in industry for cutting, cleaning, or preparing metals for subsequent fabrication operations. In the hands of a skilled operator, an air-carbon arc cutting and gouging torch can be used to remove a defect in a workpiece such as a steel plate and in removing the defect prepare the cavity for repair by a subsequent filler metal welding operation. The process also is used to prepare metals for welded construction.
2. Description of the Prior Art
The air-carbon arc cutting and gouging process was first described and claimed in U.S. Pat. No. 2,706,236. According to the process as now practiced, a carbon (graphite) electrode, normally having a copper coating, is positioned so that an arc can be struck between the electrode and the workpiece. Coincidentally, with initiation of the arc, compressed air is caused to flow down the side of the electrode following the direction of travel to forceably remove (blast away) molten metal produced by the effect of the electric arc.
A suitable hand torch for practicing the air-carbon arc process is disclosed and claimed in U.S. Pat. No. 3,573,419. All prior art torches generally provide means such as a valve to control the admission of air to the torch head which directs the air along the electrode. All of the prior art torches utilize air normally found in central high pressure air systems in factories. It has been found that this air pressure usually varies between 80 and 100 pounds per square inch (psi). Whatever air pressure is available is utilized in the practice of the air-carbon arc process as long as it will remove the molten metal from the area of the electric arc maintained between the electrode and the workpiece.
Measurements have shown that when utilizing air pressures normally found in a manufacturing plant (e.g. 80 to 100 psi), the noise level striking an operator's ear is at the level of from 120 to 125 dbA. Noise levels of this magnitude can, over a long period of time, cause damage to the ear of a constant user of the process.